// Chap 7, pp 319 - 321
// Rename this file as QueueA.cpp

// ********************************************************
// Implementation file QueueA.cpp for the ADT queue.
// Circular array-based implementation.
// The array has indexes to the front and rear of the 
// queue. A counter tracks the number of items currently 
// in the queue.
// ********************************************************

#include "QueueA.h"  // header file

// constructors and destructor:
queueClass::queueClass(): 
             Front(0), Rear(MAX_QUEUE-1), Count(0)
{
}  // end default constructor

queueClass::queueClass(const queueClass& Q):
             Front(Q.Front), Rear(Q.Rear), Count(Q.Count)
{  for (int Index = 0; Index < Q.Count; ++Index)
      Items[Index] = Q.Items[Index];
}  // end copy constructor

queueClass::~queueClass()
{
}  // end destructor

boolean queueClass::QueueIsEmpty()
{
   return boolean(Count == 0);
}

void queueClass::QueueAdd(queueItemType NewItem, 
                          boolean& Success)
{
   Success = boolean(Count < MAX_QUEUE);

   if (Success)
   {  // queue is not full; insert item
      Rear = (Rear+1) % MAX_QUEUE;
      Items[Rear] = NewItem;
      ++Count;
   }  // end if
}  // end QueueAdd

void queueClass::QueueRemove(boolean& Success)
{
   Success = boolean(!QueueIsEmpty());

   if (Success)
   {  // queue is not empty; remove front
      Front = (Front+1) % MAX_QUEUE;
      --Count;
   }  // end if
}  // end QueueRemove

void queueClass::GetQueueFront(queueItemType& QueueFront,
                               boolean& Success)
{
   Success = boolean(!QueueIsEmpty());

   if (Success)
      // queue is not empty; retrieve front
      QueueFront = Items[Front];
}  // end GetQueueFront
// End of implementation file.